Engine with oil separator

ABSTRACT

In order to remove oil from the engine, i.e. to evacuate lubricant oil from the crankcase (1), the crankcase and the rotating parts (6, 2, 3) therein are designed so that a centrifugal flow is generated in the crankcase (1) and is used to separate the engine oil from the air that surrounds it. Preferably, only a small gap (8) remains between the outermost partially cylindrical rotating parts, in particular the counterweight (6), and the inner wall of the cylindrical crankcase (1). The oil is removed through an outlet (10) that extends tangentially out of the crankcase (1).

This application is a continuation of application(s) Ser. No. 08/256,009filed on Oct. 5, 1994 now abandoned.

BACKGROUND OF THE INVENTION

One problem that exists in engines is reliable removal of oil from theengine housing during every stage of operation of the engine. The engineoil is customarily collected in a so-called sump, that is, "below" inthe crankcase outside the rotating parts, such as crankshaft,counterweight, etc., of the engine. Such a method of oil removal iscritical, for instance, in aircraft engines for acrobatic airplaneswhich remain, for a long time, substantially in upside down position,but also in conventional automobile engines when oil reaches the area ofthe rotating parts as result of transverse accelerations. Forlubrication technique reasons, it must be ensured that the removal ofoil, that is, the drawing of the oil out of the crankcase, be as free ofair as possible so that no foam forms in the oil.

It has been sought to remove the oil by additional pumps. On one hand,this involves considerable expenses and, in addition, does not ensureair-free conveyance of the oil since the pumps, which run continuously,of necessity deliver air even in the case of small amounts of oil.

SUMMARY OF THE INVENTION

The problem on which the invention is based is to ensure removal of oilby means of a simple construction which guarantees that the oil will becompletely removed from the crankcase and practically free of air.

According to the invention, this is obtained by the fact that the partsof the engine that rotate in the crankcase, that is, the crankshafts,the crankpins, the piston rods and the counterweights, are surrounded byan engine housing with a spacing such that only a small gap remainsbetween the surface circumscribing the rotating parts and the crankcaseso as to generate, in the crankcase by means of the rotating parts, acentrifugal flow which is used for conveying the oil. The oil is removedfrom the crankcase through an outlet that extends tangentially out ofthe crankcase. The centrifugal force acting upon the oil issubstantially stronger than gravity acting upon the oil and thus theoutlet can be situated at any desired place in the cylindricalcrankcase. Air and oil are necessarily separated from each other by thecentrifugal forces. By dimensioning the downflow resistance through theoutlet, it can be obtained that only oil and not air exits from theoutlet.

For the rest it is not necessary that the crankcase be adapted in shapeexactly to the external surface that circumscribes all of the rotatingparts, that is, adapted especially in shape to the rolling of thecrankshaft; it is, to the contrary, sufficient that the innerwall of thecrankcase be generally cylindrical and the crankcase be on both sides ofthe crankshaft, locked as tightly as possible to the rotating parts. Aseparate outlet is preferably provided for each cylinder.

BRIEF DESCRIPTION OF THE DRAWINGS

One embodiment of the invention is explained in detail with reference tothe diagrammatic drawings. In the drawings:

FIG. 1 is a cross section through one part of a engine;

FIG. 2 is a diagrammatic side view of an in-line four-cylinder engine.

DESCRIPTION OF THE PREFERRED EMBODIMENT

A cylindrical crankcase 1 for a crankshaft 2, with crank-pins 3 on whichare hinged piston rods 4 which lead to pistons, not shown, that slide toand fro in a cylinder 5, is shown in FIG. 1. The crankshaft 2 rotatesabout its shaft axle A. The crankshaft 2 is connected withcounterweights 6 for the piston rods and the pistons, and a small gap 8remains between the partially cylindrical underside 7 of thecounterweight 6 and the inner wall of the crankcase 1. A slide or wiper9 can also be provided on the bottom of the counterweight which slidesdirectly on the inner wall of the crankcase 1 or in a groove in theinner wall. An outlet 10, leading substantially tangentially out of thecrankcase, is provided on the cylindrical crankcase.

A side view of an in-line four-cylinder engine, with the cylindricalcrankcase 1 and the four cylinders 5, is diagrammatically shown in FIG.2. A flywheel 11 with a clutch and a ventilator 12, for cooling, areadditionally connected with the crankshaft. An outlet 10, respectivelyconnected via pipes with a reservoir 13 for the lubricating oil of theengine, is provided for each crank space.

When engine oil is in the crankcase 1, the rotating parts of thecrankshaft produce, in the cylindrical area of the crankcase 1, acentrifugal flow by which the engine oil, which may eventually bepresent in the crankcase, is driven out through the outlet 10, asindicated by an arrow 14, and collected in the receptacle 13. The oil,in turn, is led back from said receptacle into the crankcase aslubricating oil. The oil is substantially driven out by the centrifugalflow generated in the crankcase 1 and not necessarily by the mechanicalcontact with the counterweight 6 or the wiper 9.

The described oil removal takes place in all positions of the crankcase1.

It also is unnecessary for the whole crankcase to be cylindrical; onlyin a few important areas need to be designed cylindrically for oilremoval in which the oil can be introduced into the flow and dischargedvia outlet bores. The design of the counterweight 6 is particularlyimportant since, as a rule, it has the largest radius. The underside 7of the counterweight also determines said outer surface thatcircumscribes the rotating parts in the crankcase and which is to bethought of almost as a continuation of the partially cylindricalunderside of the counterweight 6. The other rotating parts in thecrankcase, especially the crankpins, of course also contribute to saidcentrifugal flow. The width of the counterweight, in the direction ofthe shaft axle A, must be selected as large as possible for a goodremoval of oil.

The described oil removal is adequate for all kinds of engines, whetherthey are diesel engines, Otto engines, in-line engines, or even radialengines. Especially for the latter, the rotating parts and the crankcasecan be very well designed according to the invention.

I claim:
 1. An engine capable of sustained operation in any orientationhaving a plurality of components comprising: a crankcase (1), acrankshaft (2) having a shaft axis, at least one piston rod (4) hingedon a crankpin (3) of said crankshaft (2), a piston, a cylinder (5), onepiston being located within each cylinder (5) and being connected withone piston rod, and the engine has at least one counterweight (6);saidplurality of components being lubricated with engine oil via lubricationpoints and being connected with means for removing oil from saidcrankcase; wherein some of said plurality of components are rotatingcomponents that rotate about said shaft axis, an inner wall of saidcrank-case (1) closely surrounds said rotating components in a mannersuch that only a small gap results between the inner wall of thecrankcase and at least one of said rotating components, said small gapbeing sufficiently small to produce, during use, an oil flow along saidinner wall, and wherein a plurality of oil outlets are provided in theinner wall of said crankcase which all extend substantially tangentiallyout of said crankcase oriented and located to receive oil flowing alongthe inner wall and discharge that oil to an oil circulation systemwhereby said rotating components produce, during use, a centrifugal flowin said crankcase (1) in which the engine oil in said crankcaseseparates from surrounding air, flows along the inner wall, is drivenout of said crankcase through said plurality of oil outlets and isconveyed to the lubrication points of said crankcase.
 2. An engineaccording to claim 1, wherein said crankcase (1) is cylindricallydesigned, at least in areas provided for discharge of engine oil, andsaid small gap (8) is provided in an area between said inner wall ofsaid crankcase and the outer surface of said counterweight (6).
 3. Anengine according to claim 2, wherein an outer surface of saidcounterweight (6) is at least partially cylindrical in shape.
 4. Anengine having a plurality of components comprising a crankcase (1), acrankshaft (2) having a shaft axis, at least one piston rod (4) hingedon a crankpin (3) of said crankshaft (2), a piston, a cylinder (5), onepiston being located within each cylinder (5) and being connected withone piston rod, and the engine has at least one counterweight (6);saidplurality of components being lubricated with engine oil via lubricationpoints and being connected with means for removing oil from saidcrankcase; wherein some of said plurality of components are rotatingcomponents (2, 3, 6) that rotate about said shaft axis, an outer surfaceof said at least one counter weight (6) is at least partiallycylindrical in shape and has a larger radius of rotation than any otherrotating component, an inner wall of said crank-case (1) iscylindrically designed, at least in areas provided for discharge ofengine oil, and closely surrounds said rotating components (2, 3, 6) ina manner such that only a small gap results between said inner wall ofsaid crankcase and said outer surface of said at least one counterweight, said small gap is sufficiently small to produce, during use, anoil flow along said inner wall, at least one oil outlet (10) is providedin said inner wall of said crankcase, said at least one oil outlet (10)extends substantially tangentially out of said crankcase, has an axissubstantially in the direction of said oil flow along said inner walland discharges into an oil circulation system connected with thelubrication points, no oil outlet (10) provided in said inner wallextends substantially tangentially out of said crankcase with an axissubstantially in an opposite direction of said oil flow along said innerwall, and a slide (9) which engages one of said inner wall and a grooveof said crankcase (1) is connected with said crankshaft (2), wherebysaid rotating components (2, 3, 6) in said crankcase (1) produce, duringuse, a centrifugal flow in said crankcase (1) in which the engine oil insaid crankcase separates from surrounding air, flows along said innerwall, is driven out of said crankcase through said at least one oiloutlet, and, thereafter, is conveyed to the lubrication points of saidcrankcase.
 5. An engine having a plurality of components comprising acrankcase (1), a crankshaft (2) having a shaft axis, at least one pistonrod (4) hinged on a crankpin (3) of said crankshaft (2), a piston, acylinder (5), one piston being located within each cylinder (5) andbeing connected with a piston rod, and the engine has at least onecounterweight (6);said plurality of components being lubricated withengine oil via lubrication points and being connected with means forremoving oil from said crankcase; wherein some of said plurality ofcomponents are rotating components (2, 3, 6) that rotate about saidshaft axis, an outer surface of said at least one counter weight (6) isat least partially cylindrical in shape and has a larger radius ofrotation than any other rotating component, an inner wall of saidcrank-case (1) is cylindrically designed, at least in areas provided fordischarge of engine oil, and closely surrounds said rotating components(2, 3, 6) in a manner such that only a small gap results between saidinner wall of said crankcase and said outer surface of said at least onecounter weight, said small gap is sufficiently small to produce, duringuse, an oil flow along said inner wall, at least one oil outlet (10) isprovided in said inner wall of said crankcase, said at least one oiloutlet (10) extends substantially tangentially out of said crankcase,has an axis substantially in the direction of said oil flow along saidinner wall and discharges into an oil circulation system connected withthe lubrication points, no oil outlet provided in said inner wallextends substantially tangentially out of said crankcase with an axissubstantially in an opposite direction of said oil flow along said innerwall, and a slide (9) which engages one of said inner wall and a grooveof said crankcase (1) is connected with said outer surface (7) of saidcounterweight (6), whereby said rotating components (2, 3, 6) in saidcrankcase (1) produce, during use, a centrifugal flow in said crankcase(1) in which the engine oil in said crankcase separates from surroundingair, flows along said inner wall, is driven out of said crankcasethrough said at least one oil outlet, and, thereafter, is conveyed tothe lubrication points of said crankcase.